Giovonny hit the nail on the head.
If you want to date a fit girl it really helps to be fit and active.
In addition to being in good shape it's helpful to have active hobbies. Get into backpacking, cross country skiing, mountain climbing, kayaking, surfing, whatever. A girl who's fit will have no problem adapting to whatever activity it is you do and it's a great way to bond quickly with someone. It's not a great idea to do those activities specifically to meet women - they're usually dominated by men and the women who are there get passed around amongst the top guys. Instead think of it as developing a lifestyle you can bring a girl into. They're all relatively solo activities that can be done with just a partner so once you're competent you can teach a girl what's up without bringing her around the guys who might tempt her away.
If you want to date a fit girl it really helps to be fit and active.
In addition to being in good shape it's helpful to have active hobbies. Get into backpacking, cross country skiing, mountain climbing, kayaking, surfing, whatever. A girl who's fit will have no problem adapting to whatever activity it is you do and it's a great way to bond quickly with someone. It's not a great idea to do those activities specifically to meet women - they're usually dominated by men and the women who are there get passed around amongst the top guys. Instead think of it as developing a lifestyle you can bring a girl into. They're all relatively solo activities that can be done with just a partner so once you're competent you can teach a girl what's up without bringing her around the guys who might tempt her away.